Patent GB-816231-A (GB)
Title: Process for the separation of acetylene-free ethylene from gas mixtures
IPC: C07C7/11
Filed: 1956-04-27
Abstract: <PICT:0816231/III/1> Ethylene free from acetylene is obtained from a gas mixture containing low aliphatic hydrocarbons by separating therefrom a C2 hydrocarbon stream by rectification, removing ethane by rectification, absorbing acetylene in a selective liquid solvent at a temperature at or near the liquefaction temperature of the C2 hydrocarbon stream, separating liquid ethylene by rectification from the effluent and using part of the liquid ethylene so obtained as a scrubbing liquid during the separation by rectification of said liquid ethylene, the greater part of ethylene absorbed in the selective solvent being regenerated by heat exchange with regenerated solvent and regenerating the solvent by heating and recovering acetylene and residual ethylene; in a modification, ethane is not removed prior to the acetylene absorption and the ethane-ethylene mixture recovered from the solvent by heat exchange with regenerated solvent is rectified to obtain liquid ethylene part of which is used as a scrubbing liquid in the solvent absorption of the acetylene. The selective solvent is preferably acetone mixed with liquid ethylene.  Referring to Fig. 1, a C2 cut enters distillation column 2 by line 1, liquid ethylene being supplied at the head by line 5 from the product stream; ethane is withdrawn by line 4.  An acetylene-ethylene mixture passes by line 3 to scrubbing tower 12 fed with acetone by line 13 and liquid ethylene by line 15; product ethylene leaves by line 6 and is liquefied.  Solvent containing acetylene and ethylene is heated in heat-exchanger 24 by regenerated solvent liberating ethylene which is returned to the base of the scrubber by line 25.  The solvent is regenerated in tower 27 and returned via heat-exchanger 24 to the scrubber. Acetylene together with some ethylene is recovered by line 28. The liquid ethylene supplied to the top of scrubber 12 may alternatively be obtained by partially liquefying the ethylene effluent with a refrigerating coil in the head of the scrubber using product ethylene as the refrigerating liquid.ALSO:Ethylene free from acetylene is obtained from a gas mixture containing low aliphatic hydrocarbons by separating therefrom a C2 hydrocarbon stream by rectification, removing ethane by rectification, absorbing acetylene in a selective liquid solvent at a temperature at or near the liquefaction temperature of the C2 hydrocarbon stream, separating liquid ethylene by rectification from the effluent and using part of the liquid ethylene so obtained as a scrubbing liquid during the separation by rectification of said liquid ethylene, the greater part of ethylene <PICT:0816231/IV (b)/1> absorbed in the selective solvent being regenerated by heat exchange with regenerated solvent, and regenerating the solvent by heating and recovering acetylene and residual ethylene; in a modification, ethane is not removed prior to the acetylene absorption and the ethaneethylene mixture recovered from the solvent by heat exchange with regenerated solvent is rectified to obtain liquid ethylene part of which is used as a scrubbing liquid in the solvent absorption of the acetylene.  The selective solvent is preferably acetone mixed with liquid ethylene. Referring to Fig. 1, a C2 cut enters distillation column 2 by line 1, liquid ethylene being supplied at the head by line 5 from the product stream; ethane is withdrawn by line 4.  An acetylene-ethylene mixture passes by line 3 to scrubbing tower 12 fed with acetone by line 13 and liquid ethylene, by line 15; product ethylene leaves by line 6 and is liquefied.  Solvent containing acetylene and ethylene is heated in heat-exchanger 24 by regenerated solvent liberating ethylene which is returned to the base of the scrubber by line 25. The solvent is regenerated in tower 27 and returned via heatexchanger 24 to the scrubber. Acetylene together with some ethylene is recovered by line 28. The liquid ethylene supplied to the top of scrubber 12 may alternatively be obtained by partially liquefying the ethylene effluent with a refrigerating coil in the head of the scrubber using product ethylene as the refrigerating liquid.